[Determination of irreversibility of clinical brain death. Electroencephalography and evoked potentials]

[Digital electroencephalography in brain death diagnostics : Technical requirements and results of a survey on the compatibility with medical guidelines of digital EEG systems from providers in Germany]

BACKGROUND

The guidelines of the German Medical Association and the German Society for Clinical Neurophysiology and Functional Imaging (DGKN) require a high procedural and technical standard for electroencephalography (EEG) as an ancillary method for diagnosing the irreversible cessation of brain function (brain death). Nowadays, digital EEG systems are increasingly being applied in hospitals. So far it is unclear to what extent the digital EEG systems currently marketed in Germany meet the guidelines for diagnosing brain death.

METHODS

In the present article, the technical und safety-related requirements for digital EEG systems and the EEG documentation for diagnosing brain death are described in detail. On behalf of the DGKN, the authors sent out a questionnaire to all identified distributors of digital EEG systems in Germany with respect to the following technical demands: repeated recording of the calibration signals during an ongoing EEG recording, repeated recording of all electrode impedances during an ongoing EEG recording, assessability of intrasystem noise and galvanic isolation of measurement earthing from earthing conductor (floating input).

RESULTS

For 15 of the identified 20 different digital EEG systems the specifications were provided by the distributors (among them all distributors based in Germany). All of these EEG systems are provided with a galvanic isolation (floating input). The internal noise can be tested with all systems; however, some systems do not allow repeated recording of the calibration signals and/or the electrode impedances during an ongoing EEG recording.

CONCLUSION

The majority but not all of the currently available digital EEG systems offered for clinical use are eligible for use in brain death diagnostics as per German guidelines.

Research on the cause of death for severe stroke patients

AIMS AND OBJECTIVES

To explore the characteristics of mortality among severe stroke patients, analyse their causes of death and provide evidence for improving the survival rate of stroke patients.

BACKGROUND

Stroke is an important fatal and disabling disease that poses a large burden on its patients, and its high death rates have caused substantial concern to the World Health Organization.

DESIGN

A retrospective case-control study.

METHODS

A total of 188 patients who died of stroke in the neurological intensive care unit of the First Affiliated Hospital of Chongqing Medical University from January 2012-December 2015 were selected as cases. Additionally, 188 stroke survivors from the same neurological intensive care unit were randomly selected as paired cases. The clinical characteristics of the severe stroke patient deaths were analysed, and a univariate analysis was conducted to determine potential mortality risk factors. A logistic regression analysis was then conducted to determine the independent risk factors of mortality.

RESULTS

We investigated a total of 231 cases of death in neurological intensive care unit patients, 188 of whom died of stroke. Therefore, the death rate from stroke accounted for 81.3% of the total population, with ischaemic, haemorrhagic and mixed strokes accounting for 47.19%, 26.84% and 7.36% of the patients, respectively. The leading cause of death was central nervous system-related causes (central respiratory and circulatory failure, brain herniation), followed by multisystemic causes. The independent risk factors of death among the neurological intensive care unit patients were as follows: brain herniation (OR = 18.15), multiple organ failure (OR = 13.12), dyslipidemia (OR = 4.64), community-acquired lung infection (OR = 4.15), use of mechanical ventilation (OR = 3.37), hypoproteinemia (OR = 2.29), history of hypertension (OR = 2.03) and hospital-acquired pneumonia (OR = 1.75).

CONCLUSIONS

The most common cause of death in stroke patients was damage to the central nervous system. Independent risk factors were brain herniation, multiple organ failure, dyslipidemia, community-acquired lung infection, the use of mechanical ventilation, hypoproteinemia, a history of hypertension and hospital-acquired pneumonia. Clinicians should be aware of the presence and possible effects of these conditions. Early prevention, monitoring and intervention to modify controllable risk factors will improve patient prognosis.

RELEVANCE TO CLINICAL PRACTICE

Clinicians should be aware of the multiple independent risk factors of death and implement timely treatment measures to reduce the incidence of death in severe stroke patients.